Warp size containing dicyandiamide and a polyacrylate salt



United States Patent Q WARP SIZE CONTAINING DICYANDIAMIDE AND A POLYACRYLATE SALT New York, N. Y., a corporation of Maine No Drawing. Application July 6, 1954 Serial No. 441,678

13 Claims. (Cl. 28-80) This invention relates to warp sizes and warp sizing processes.

A wide variety of materials have been used as Warp s zes to improve the weaving characteristics of yarns derived from various fibers. A considerable number of these compositions have been successful and many advances have been made in the art of sizing warp yarns for the pnrnary purpose of protecting them during weaving. Nevertheless there is always a demand for better warp sizes and also for less expensive warp sizes.

An object of the present invention is to improve the abrasion resistance of warp yarns.

Another object of the invention is to provide an improved warp size;

A further object of the invention is to provide a non-acidic size for nylon yarns.

Other objects and advantages of the invention will be apparent to those skilled in the art upon consideration of the detailed disclosure hereinbelow.

It has been found that greatly improved weaving can be obtained, at lower cost in the case of many yarns, by Warp sizing textile yarns with a composition comprising a substantially nonacidic warp sizing material, dicyandiamide and a reaction product of a monovalent base having a dissociation constant of at least l.8 lwith a polymer of a compound of the group consisting of acrylic acid, acrylonitrile, acrylamide and lower alkyl acrylates.

The novel process may be employed with any textile fiber which is ever subjected to warp sizing, but is expected to have maximum utility in the field of synthetic textile fibers such as nylon of both the adipamide and the caprolactam types; polyesters including cellulose acetate, other cellulose esters and polyethylene glycol terephthalate; copolymers of vinyl chloride and vinylidene chloride; acrylic fibers containing homopolymers of acrylonitrile and copolymers thereof With vinyl acetate, methyl acrylate, vinyl pyridine and other suitable comonomers, as well as the cellulose fibers derived from viscose and cuprammonium rayon.

The present compositions contain three essential ingredients plus any desirable compatible additives, that is, additives which do not destroy the warp sizing characteristics and which do not precipitate the sizing agent from solution or dispersion in water. The major ingredient of these new compositions is a substantially nonacidic warp sizing agent, which expression is used here to denote warp sizes having a pH of at least 4.0 in a aqueous solution or dispersion. Among the many suitable substances are gelatine, glue, polyvinyl alcohol, starch and water-soluble salts of styrene-maleic anhydride copolymers.

Another essential component of the present sizing agents is dicyandiamide and no equivalents are known for this material for the present purposes. The quantity of dicyandiamide may range from about 10 to about 75% of the weight of the conventional warp sizing agent,

ice

2 but optimum results are usually obtained with between 20 and 60% dicyandiamide. p

The compositions disclosed herein must also contain a reaction product of a monovalent base having a dissociation constant of at least 1.8x 10" with an acrylic polymer obtained by polymerizing acrylic acid, acrylonitrile, acrylamide or a lower alkyl acrylate. These reaction products are water-soluble or at least water-dispersible depending on the molecular weight. To effect the desired improvement in warp sizing characteristics between about 10 and about 50 parts of the reaction product should be present for every 100 parts by weight of the conventional warp sizing component. Less than 10 parts does not produce sutficient improvement in abrasion resistance and above about 50 parts tends to produce excessive tackiness on the yarn being treated.

At a 10% concentration by weight, the present aqueous sizing baths have a pH of at least 5 and usually below 9 unless it is desired to increase the alkalinity of the size by addition of an alkali or by not neutralizing the hydrolyzed polyacrylic compound in the manner described below. I

In preparing the aforesaid reaction products the acrylic acid derivative is polymerized in amanner well known to those skilled in the art, as, for example, in aqueous dispersion in the presence of a conventional oxygencontaining polymerization catalyst or a redox polymerization catalyst. Accordingly, the details of preparing this polymer are not given herein. The acrylic polymer is then neutralized, hydrolyzed or saponified by reaction'with a strong monovalent base having a dissociation constant of at least 1.8 l0- at 25 C. Sodium and potassium hydroxides are preferred for the purpose but the carbonates of these alkali metals may also be used as Well as ammonium hydroxide. Hydrolyzed polyacrylonitrile is preferred for the purpose by reason of the ready availability of acrylonitrile. In preparing this material an aqueous slurry containing 12 or 13% of polyacrylonitrile is mixed with a 50% aqueous solution of caustic soda containing 0.8 mol of sodium hydroxide for each mol of acrylonitrile calculated as the monomers. The 'saponification or hydrolysis reaction is carried out about 95 C. with continual stirring. Then the free alkali is usually partially neutralized with sulfuric acid in suflicient amount to reduce the pH of a sample diluted to about a 5% solids content to between 7 and 11. By varying the reaction conditions and especially the amount of sodium hydroxide, the degree of hydrolysis may be varied from about 50% up to complete hydrolysis. Excellent results have been obtained with polyacrylonitrile which is 65 to hydrolyzed. This means that 65 to 70% of the nitrile groups have been converted into-COONa radicals, and most of the balance of the nitrile groups have been changed into-CONH2 groups. Accordingly, it may be said that hydrolyzed polyacrylonitrile is of the same general nature as an alkali orammonium polyacrylate. The molecular weight of these polyacrylate reaction products does not appear to be critical, but it is thought that it should amount to at least 10,000 and preferably not over 1,000,000. 0 The compositions of the present invention possess a wide variety of valuable features. In one sense they may be regarded as conventional warp sizing agents in combination with additives which improve the agent greatly. Gelatine is a well known commercial warp size that has been completely unsatisfactory on filament nylon yarns by reason of the excessive shedding resulting from poor adhesion. Accordingly, weavers have turned to the use of polyacrylic acid which is far more expensive, and moreover requires special costly equipment such as stainless steel slashers, etc. to prevent corrosion with consequent staining of the yarn. With the preferred sizing baths of the present invention, which are of a neutral orslightly alkaline character, conventional mill equipment can be'used. Moreover, when dicyandiamide and a 4. and are applied to filament yarns composed of cellulose acetate, viscose and 100 denier nylon prepared by the adipamide process. The bath is maintained at l20-140 F. and after immersion therein the yarns are passed between squeeze rolls adjusted to produce a wet pick-up e v e D polyacrylateof the type disclosed herein are added in of about 100%. After drying, at least five samples of small quantities to gelatine or glue, the size not only each of the three yarns are conditioned and then subjected stays on the nylon and other yarns without shedding to an abrasion. test on a modified Walker yarn abrader but exceptionally high abras on resistance is produced. at 100 grams tension. Thus the tabulated number of similareifects are obta ned with other conventional sizing 1Q abrasion cycles represents an average rather than a single agents such as polyvinyl alcohol and the sodium salt of value. a copolymer of styrene and maleic anhydride, on textile Examples E, F, G and H are carried out under similar yarns in general and especially on the artificial fibers. conditions but it is believed. that Example E is a more The, novel sizing compositions produce a highly desirable satisfactory control example for. this group than Exstiifening without embrittlement of the warp yarns, and 15 ample A. this distinctly enhances the weaving characteristics of Examples J, 10 and 11 differ in that the filament nylon the y In addition, the present Sizes have displayed yarn employed therein is of 90 denier rather than 100 stability for prolonged periods over a wide range of denier and, furthermore, polyacrylic acid size is used temperatures not only in the dry, powderedform but also in Example I.

Table Examples "A B 1 2 3 o 4 5 6 B 7 s 9 E F G H J 10 11 Percentin Size Bath: I

Stymer S1 Gelatine .1 Polyvinyl Alcohol. 0. 5) Hydrolyzed Polyacrylonit'rile 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 0.4 0.4 Dlcyandiamide 0.5 1.0 2.0 0.5 1.0 2.0 0.5 1.0 2.0 0.5 1.0 2.0 1.5 1.5 Abrasion Tests:

Acetate Cycles 327 427 456 536 481 473 619 663 510 512 641 655 615 383 355 381 393 Percent Increase 39 63 47 31 s 25 2s 20 -7 ,1 3 Visc0se.-

Cycles 170 296 810 1,066 929 287 537 550 468 443 1,425 1,638 864 163 157 202 201 Percent In- Nl crease 74 376 526 476 87 92 63 228 278 98 "-4 24 24 yon Cycles so 133 166 173 141 69 206 215 147 71 144 144 134 810 2,166 1,456 Percent In crease 66 107 116 200 210 113 101i 103 as I A trademark of the Monsanto Chemical Company which is used for the water-soluble sodium salt of a copolymer of styrene and maleic anhydride.

3 The warp sizing bath in Example I consists of an aqueous dispersion of 4.2%

free of polyvinyl alcohol but contains 0.5% ota refined light mineral oil admixed with a very small amount 3 The warp sizing bath in Example 11 is oian emulsifying agent.

upon dilution to the usual concentration of a size bath. Further, upon testing with conventional scouring solutions, it was found that removal of the size in the usual manner was quite satisfactory. When dicyandiamide and a polyacrylate are added to low viscosity starch sizes, the composite sizing material appears to have a far more stable viscosity than without the above additives.

Size baths prepared according to the present invention may range from 1 to about 20% by Weight of solids in dispersion or solution, but between 3 and 10% is recommended. These baths are prepared simply by mixing the dry powdered size into Water and heating the mixture to about F. It is usually preferred .to pass the warps through a bath maintained at 120 to 150 F. Depending on the type of yarn and the squeeze roll adjustment, the wet pick-up customarily runs between 70 and 150%. The dry pick-up on the yarn may range from about 1 to about 15% and the best results are usually obtained at from 3 to 8%.

For a better understanding of the nature and objects of this invention reference should be had to the following examples in which proportions are given in terms of weight unless otherwise stated therein. Letters are used to denote comparative examples and numerals are employed to designate illustrative examples in the practice of the present invention.

EXAMPLES Comparative Examples A to D and illustrative Examples l to 9 inclusive in the table below are performed under. uniform conditions unless specified otherwise in the table. Aqueous warp sizing baths are prepared employing the proportions of solids listed below polyacrylic acid and is free of polyvinyl alcohol.

Referring to the tabulated data, it will be observed that Examples A, C, D' and E are control or comparative examples which demonstrate the effect of certain conventional warp sizing materials; Comparative Example B shows that only a moderate improvement in abrasion resistance is obtained by adding hydrolyzed polyacrylonitrile alone to the warp size of Example A. Comparative Examples F, G and H demonstrate that the addition of varying quantifies of dicyandiamide alone to the same warp size produces no significant improvement in abrasion resistance on the treated yarns. On the other hand when the abrasion tests made in connection with illustrative Examples-1, 2 and 3 are compared with control Example A, illustrative Examples 4, 5 and 6 are compared with control Example C and illustrative Examples 7, 8 and 9 with control Example D, it is clear that the addition of both hydrolyzed polyacrylonitrile and dicyandiamide to conventional nonacidic warp sizing materials produces a striking improvement in the abrasion resistance of the various treated yarns. In Examples 1, 10 and 11 warp sizing is carried out on a different grade of nylon under generally comparable conditions. It will be observed that a striking improvement in abrasion resistance is also realized by the compositions of the present invention over a commercial polyacrylic acid dispersion which is widely used in sizing filament nylon and which requires the use of corrosion-resistant slashers. Examples 11 demonstrates that the present sizes are compatible with mineral oil dispersions where a greater lubricating eifect is sought. For some purposes the oil emulsion is undesirable as it'tends to reduce the resistance to abrasion produced by the prsent' sizes.

EXAMPLE 12 A size is prepared by blending the following materials in the dry state:

Percent Bone glue powder, 100 mesh 72.7 Hydrolyzed polyacrylonitrile 9.1 Dicyandiamide 18.2

This size is dissolved in water at 140 F. to a concentration of solids to form a warp sizing bath. Nylon of the adipamide type, cotton, polyethylene glycol terephthalate, cellulose acetate, viscose and three acrylic filament yarns are passed through a slasher with the squeeze rolls set for a wet-pickup of approximately 100%. Next, the impregnated yarn is dried for about 10 minutes at 240 F. The three acrylic fibers are homopolymeric' acrylonitrile, a copolymer of 95% acrylonitrile and 5% methyl acrylate and a copolymer of 40% acrylonitrile and 60% vinyl acetate. In these sizing operations, superior splitting is obtained and no difiiculty is encountered with foaming or shedding. In addition all of the yarns are examined for stiffness, flexibility and tackiness at 70 F. and 80% relative humidity and are found to be eminently suitable for weaving in addition to displaying superior resistance to abrasion. From scouring tests on both cotton fabric and nylon fabric using 180 F. water containing 0.1% sodium carbonate and 0.1% soap for 10 minutes, it is apparent that the novel sizes are readily removed to a satisfactory degree using a light scour.

EXAMPLE 13 Example 12 is repeated with a similar size composition of somewhat diflferent proportions. This size is composed of Substantially the same results are obtained as in Example 12 While the above examples are directed at a limited number of conventional warp sizing agents and a relatively limited number of yarns in order to facilitate comparison of the results obtainable with the present warp sizing compositions, it is to be understood that this is not intended to delineate the field of the present compositions which extends to all compatible sizing materials; that is, those of a substantially neutral or of an alkaline nature.

Accordingly, while there are above disclosed only a limited number of embodiments of the composition and process of the invention herein presented, it is possible to produce still other modifications without departing from the inventive concept herein disclosed, and it is desired therefore that only such limitations be imposed on the appending claims as are stated therein, or required by the prior art.

We claim:

1. A composition of matter which comprises a substantially nonacidic textile warp sizing material capable of exhibiting a pH of at least 4.0 when in the form of a 10 percent aqueous solution, dicyandiamide and a product self-dispersible in water and having a molecular weight of at least about 10,000 of the reaction of a monovalent base having a dissociation constant of at least l.8 10- with a polymer of a compound of the group consisting of acrylic acid, acrylonitrile, acrylamide and lower alkyl acrylates.

2. A composition of matter which comprises 100 parts on a dry weight basis of a substantially nonacidic textile warp sizing material capable of exhibiting a pH of at least 4.0 when in the form of a 10 percent aqueous solution,

between about 10 and about parts of dicyandiamide and between about 10 and about 50 parts of a product self-dispersible in water and having a molecular weight of at least about 10,000 of the reaction of a monovalent base having a dissociation constant of at least 1.8 10* with a polymer of a compound of the group consisting of acrylic acid, acrylonitrile, acrylamide and lower alkyl acrylates.

3. A composition of matter according to claim 2 in which the warp sizing material comprises gelatine.

4. A composition according to claim 2 in which the warp sizing material comprises polyvinyl alcohol.

5. A composition according to claim 2 in which the warp sizing material comprises a water-soluble salt of a copolymer of styrene and maleic anhydride.

6. A composition of matter which comprises parts on a dry weight basis of a substantially nonacidic textile warp sizing material capable of exhibiting a pH of at least 4.0 when in the form of a 10 percent aqueous solution, between 20 and 60 parts of dicyandiamide and between 10 and 50 parts of a product self-dispersible in water and having a molecular weight of at least about 10,000 of the reaction of a monovalent base having a dissociation constant of at least 1.8 10- with a polymer of a compound of the group consisting of acrylic acid, acrylonitrile, acrylamide and lower alkyl acrylates.

7. A composition of matter which comprises dicyandiamide and a product self-dispersible in water and having a molecular weight of at least about 10,000 of the reaction of a monovalent base having a dissociation constant of at least 1.8x 10- with a polymer with the compound of the group consisting of acrylic acid, acrylonitrile, acrylamide, and lower alkyl acrylates.

8. A fabric comprising woven warp yarns wherein said yarns are sized with a composition of matter according to claim 1.

9. A fabric comprising woven warp yarns wherein said yarns are sized prior to weaving with a composition of matter according to claim 1.

10. A fabric comprising woven warp yarns wherein said yarns are sized prior to weaving with a composition of matter according to claim 2.

11. A fabric comprising woven filament warp yarns wherein said yarns are sized prior to weaving with a composition of matter according to claim 3 and wherein said yarns contain between about 1 and about 15% of said composition based on the dry weight of untreated yarn.

12. A fabric comprising woven filament warp yarns containing nylon fibers wherein said yarns are sized prior to weaving with a composition of matter according to claim 3 and wherein said yarns contain between about 1 and about 15% of said composition based on the dry weight of untreated yarn.

13. A fabric comprising woven filament warp yarns wherein said yarns are sized prior to weaving with a composition of matter according to claim 4 and wherein said yarns contain between about 1 and about 15% of said composition based on the dry weight of untreated yarn.

References Cited in the file of this patent UNITED STATES PATENTS 1,976,679 Fikentscher et a1. Oct. 9, 1934 2,184,310 Meigs et al. Dec. 26, 1939 2,482,879 Schmutzler Sept. 27, 1949 2,489,181 Hechenbleikner Nov. 22, 1949 2,686,137 Rossin et al. Aug. 10, 1954 OTHER REFERENCES Chemical Abstracts, 1948, vol. 42, pp. 2439g and 7835a. 

1. A COMPOSITION OF MATTER WHICH COMPRISES A SUBSTANTIALLY NONACIDIC TEXTILE WARP SIZING MATERIAL CAPABLE OF EXHIBITING A PH OF AT LEAST 4.0 WHEN IN THE FORM OF A 10 PERCENT AQUEOUS SOLUTION, DICYANDIAMIDE AND A PRODUCT SELF-DISPERSIBLE IN WATER AND HAVING A MOLECULAR WEIGHT OF AT LEAST ABOUT 10,000 OF THE REACTION OF A MONOVALENT BASE HAVING A DISSOCIATION CONSTANT OF AT LEAST 1.8 X 10**-5 WITH A POLYMER OF A COMPOUND OF THE GROUP CONSISTING OF ACRYLIC ACID, ACRYLONITRILE, ACRYLAMIDE AND LOWER ALKYL ACRYLATES. 